Internal-combustion engine.



G. C. DAWSON & J. W ANDERSON.

INTERNAL COMBUSTION ENGINE.

M'PLHZATION FIL ED MAR 13. 1915.

Patented Feb.

G. C. DAVISON & l. W. ANDERSON. INTERNAL COMBUSTION ENGINE. APPLICATION FlLEb MAR A TTORNEYS Patented Feb. 6,1917

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PATENT GREGORY O. :oAvIsOn AND JOHN w. annnnsoiv, or new LONDON, connnc'ricu'r, AssIGnoRs TO ELECTRIC soar (IQME'ANY, or new YORK, a. Y., A CORPORATION OF NEW JERSEY.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Fatent.

Patented net. e, 191?.

Application filed March 13, 1915. Serial No. 14,072.

To all whom it may concern:

Be it known that we, (humour (J. Dawson and JOHN XV. AivnnnsoN, citizens of the United States, residing at New London, in the county of New London and State of Connecticut, have invented certain new and useful Improvements in Internal-Combustion Engines; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to internal combustion engines and is directedto the provision of an improved form of valve mechanism for an internal combustion engine which is both reversible and self-starting.

While features of the invention may be employed in engines of various types, the invention is of special utility in two-cycle Diesel engines employing air under pressure for scavenging and for starting.

One of the primary objects of the invention is to provide a very simple construction for a reversible, self-starting Diesel engine, and particularly one in which a substantial reduction is effected in the number of valves required upon the heads'of the cylinders. In the construction heretofore employed in two-cycle self-starting Diesel engines, it has been common to provide a spray valve, one or more scavenger valves and an air-starting valve upon the head of. the working cylinder and suction and discharge valves upon the scavenger cylinders. In reversing such an engine, all of these valves, except such of them as are automatic, must have their timing altered to adapt them for operation in the new direction. Furthermore. a starting valve on the working cylinder is exposed to high pressure and temperature and when starting the engine the cylinder is sub ected to Wld temperature variations due to expansion of the air as it enters the hot cylinder. In accordance with the present invention, many of these 0bjectionable charzwteristics of former types of two-cvcle reversible self-startin en ines areeliminate .l. Among other things, it permits of removing all of the valves from the cylinder heads excepting only the fuel inlet The scavenger valves are replaced by ports in the cylinder walls controlled by the movement of the piston itself and starting is cli'ected by employing the scavenger cylinders as starting cylinders.

As a result, there are only two valves per cylinder in operation while the engine is running, only one of these is subjected to high pressure and temperature and when reversing, it is only necessary to change the timing of the spray valves and scavenger pump valves.

In the accompanying drawings which illustrate the preferred embodiment of the invention, Figure l is a view in side elevation of an engine embodying the invention, parts being shown in section, Fig. 2 is a plan view of the engine, F ig. 3 is a sectional view on line 3-3 of Fig. 2, Fig. i,

-is a sectional view on line ii of Fig. 2,

Fig. 5 is a sectional view on line 5 of Fig. 2, and Fig. 6 is a detail sectional view of the cam shaft shifting mechanism.

Referring to the drawings in which, for purposes of illustration, an engine of the two-cylinder type is shown, 1 indicates the working cylinders and 2 indicates the pump or scavenger cylinders, these being formed '4. The pistonin each cylinder structure is stepped as shown to provide a piston 5 in each worklng cylinder and a. piston 6 in each scavenger cylinder. The scavenger piston carries a. wrist pin 8 upon which is mounted one end of a connecting rod 9, the other end of which is connected to a crank on the crank shaft 10, it being understood that the cranks on the crank shaft to which the rods 9 are connected, are set at an angle of 180 from each other.

A cam shaft 11 is mounted for rotation in'bearings in the engine housing and is adapted to be driven by the crank shaft and at the same speed, as hereinafter described. It carries a cam 12 adapted to engage a. roller 13 secured to the lower end of a rod 14: which is adapted to reciprocate in an opening in the engine casing. The upper end of rod 14 is connected to the spray valve 4 by a lever 15 pivotally supported by a suitable bracket 16. The rod 14 is normally held in its raised position, in which position the valve 4 is closed, by means of a spring 17 which surrounds the rod 14 and which engages a shoulder 18 upon the rod at one end and the engine casing at the other. As the cam shaft 11 rotates, the cam 12 engages the roller 13 periodically, forcing the 'rod 14 downward and thereby opening the valve 4 to-permit fuel to be sprayed into the combustion chamber 3, the valve being again closed by the upward movement of the rod effected by spring 17 when the cam 12 moves past roller 13.

Extending through the wall of the working cylinder adjacent its lower end and adapted to be uncovered by the working piston when in its lowermost position, are the scavenger port 19 and the exhaust port 20, which ports are preferably diametrically opposite each other. The scavenger port communicates with a'receiver 21 and the exhaust port communicates with an exhaust header 22.

Referring to Fig. 1', mounted upon the en'- gine casing is a valve 23 having upper and lower chambers 24 and 25, and an intermediate chamber 26, the upper chamber communicating with one of the scavenger cylinders (as by a pipe A. Fig. 4;) and the lower chamber communicating with the other of the scavenger cylinders, (as by a pipe B, Fig. 4), and both chambers being adapted to be placed in communication with the intermediate chamber 26. Reciprocatingly mounted within the casing 23 is a hollow piston valve 27 having a reduced central portion 28 and provided with a piston rod 29 connected to an eccentric strap 30 on an eccentric 31, This eccentric is splined upon a shaft 32 which is mounted for rotation in hearings in the engine casing and adapted to be driven by the crank shaft 10 and at the same speed, as hereinafter described. The chambers in the valve casing 23 and the piston valve 27 are so proportioned and arranged that, as the piston 27 reciprocates, the upper and lower chambers 24 and 25 will be placed alternately in communication with the intermediate chamber 26 and with the scavenger receiver 21, whereby the scavenger cylinder in which the piston is making its pumping or compression stroke is placed in communication with the scavenger receiver, and the scavenger cylinder in which the piston is making its suction stroke is placed in communication with the atmosphere, as hereinafter explained in detail.

Alongside of the valve casing 23 is the valve casing 33 of an airstarting device provided with an upper chamber 34 adapted to receive compressed air from a suitable source of supply beyond a pipe 34, a lower chamber 35 which is open to the atmosphere.

and an intermediate chamber 36. This chamber 36 communicates with the intermediate chamber 26 of the valve 23 as shown in Fig. 1 and normally it is in communica valve is forced downward moving roller 40 tion with the lower chamber 35 leading to the atmosphere, the parts being then in the positions in which they are shown in Fig. 3. Positioned within the casing 33 is a piston valve 37 which 'is normally held stationary in its raised inactive. position by mea' s of a spring 38. The piston 37 is provided with a piston rod 39 carrying a roller 40 at its lower end. When the spring 38 positions the piston 37 inactively, the port 35 ot'the valve 33 opens the valve to the atmosphere. Upon pressure being applied to the upper end of the valve 37 by permitting compressed air to enter the chamber .34, the

into engagement with one or the other of two cams 41 and 42 secured to the cam shaft 32, whereby the valve is rcciprocated within its casing while being subjected to the action of the compressed air. The cams 41 and 42 are similarly shaped though they are displaced angularly about shaft 32 by approximately ninety degrees; each cam has two raised portions so that each is adapted to cause the valve 37 to make two complete rcciprocations during each 1' \'olution of the crank shaft. Also, the partsarc so a rranged that during each reciprocation of the valve 37, the intermediate chamber 36 is placed in communication alternately with the upper and lower chambers 34 and 35, as hereinafter explained in detail.

The operation of the parts thus con strncted will now be described, in detail, step by step, reference being had to Figs. 3 and 4. In order to start the engine, compressed air from a source of supply beyond the pipe. 34 is admitted into chamber 34 of the valve 33, thus forcing the piston 37 downward so that the air may flow into the intermediate chamber 36, and then into the intermediate chamber 26 of the valve 23. 'lhcreupon, the engine will be started and run on air, by cmploying the. scavenger cylinders 2 and their pistons 6 as starting motors, each of the pistons 6 being alternately subjected to a charge. of ('rompresscd air to perform its power stroke, this air being fed to the piston from the beginning to near the end of its down-strolw. and each of the pistons being alternately served by the exhaust port 35 when near the end of its up-stroke and immediately after the. air supply is cut off to the other piston which is nearing the end of its down-stroke. Thepistons 37 and 27 altcrnatcly rise and fall to take up in succession the correlated dispositions described below, in order to bring about alternately a charge of compressed air and an exhaust for each scavenger cylinder once for each revolution of the crank shaft 10. Since the chambers 24 and 26 of the valve 27 communicate respectively with the left and right-hand scavenger cylinders of Fig. 1, these scavenger cylinders will be referred to hereimrl'teras the A and 1% cylinders respectively. 1

Still referring: to Figs. 3 and i, assume that the piston in the A cylinder at the end o'l its lip-stroke. At this instant a charge of compressed air is ted to the A cylinder, this charge lasting: until the piston in the A cylinder is near the end of its downstroke and the piston in the B cylinder near the end of its lip-stroke. Then the exhaust for the B cylinder is opened and remains open until the piston in the B cylinder reaches the end of its up-stroke and the piston in the A cylinder reaches the end o'l' its down-stroke. Then a charge of compressed air is fed to the B cylinder. this charge lasting: until the piston in the ll cylinder; is near the end of its down-stroke and the piston in the A cylinder is near the end ol its up-st1. okc. Then the exhaust for the A cylinder is opened and remains open until the piston in the A cylinder reaches the end of its upstroke and the piston in the B cylinder reaches the end of its downstrokc, and so on. The valves 23 and 1 are so designed and, the pistons 27 and 37 are so timed, that these results are brought about as l'ollows: rissume that the cam-shaft is rotating in. the direction of the arrows 32 and therefore the-crankshaft 10 is rotating in the direction of the arrows 10 and that the piston in the A cylinder has just reached almost the end of its tip-stroke and thereiore the A cylinder is now about ready to exhaust. The piston 27 has just descended to break connnunication between chambers 24 and 26. The chamber 2% leads to the upper part of the B cylinder through the pipe B, and the chamber 26 communicates with the chamber 36 of the valve 33. Also, the piston 37 has just been raised to place the chamber 36 of the valve 33 in communication with the atmosphere. A very slight further rotation of the eccentric 31 in the direction of the arrow 32 lowers the piston 27 to place the chamber 26 in communication with the chamber 25. iherefore, during the latter part of the upstroke of the piston in the A cylinder, the valve piston 37 is held raised and the valve piston 27 is descending toward its lowermost position, so that the A cylinder is permitted to exhaust through the caambers 25, 26, 36 and 35 and the port 35'. Just as the piston in the A cylinder reaches the limit of its up-strokc, in readiness to receive a charge of compressed air during the greater part of the down or power stroke which it must next make, the valve piston 37 is quickly lowered to place the compressed air pipe 34 in communication with the chamber 26 of the valve 23. The valve piston 27 is at this instant slowly rising from its lowermostposition, and sochamber 26 is stilljm communication with the chamber 25 vhicli leads to the upper part of the A cylexisted at the beginning of the cycle inder. '..lherefore, a charge of com n-essed air from pipe 3% flows into the A q-linder to act upon the piston therein to drive the latter down. Simultaneously th'cqliston in the l) cylinder will rise on its upstroke, and when this piston in the ll cylinder has just reached almost the end of its up-stroke, this B cylinder is about ready to exhaust. Meanvhilo the valve piston 27 has been slowly rising from its lowermost position, and at this instant the valve piston 27 is again in the position illustrated in Fig. 4, having just broken communication between chamhers 25 and 26 of the valve 23. Also, the valve piston 37 has just been quickly raised to place chamber 36 of the valve 33 in com munication with the atmosphere through port 35. A very slight :t'urther rotation of the eccentric 31 in the direction of the arrow 52 raises the valve piston 27 to place the chamber 25 in cormnunication with the chamber 24. Therefore, during the latter part of the rip-stroke of the piston in the B cylinder, the B cylinder is permitted to exhaust through the chambers 24, 26, 36 and Hand the port 35'.

dust the piston ol' the ll cylinder reaches the limit oi" its tip-stroke, in readiness to receive a charge of compressed air during the greater part of the down or power stroke which it must neat make, the valvepiston 37 is quickly lowered to place the compressed air pipe Si in (fOlllllllllllCtl tion with the chan'lher 26 of the valve 23. The valve piston 27 is at this instant slowly descending from its highest position and so chamber 26 is still in communication with the chamber 24, which leads to the upper part of the B cylinder through the pipe B. Therefore a charge of compressed air from the pipe 34 flows into the B cylinder to act upon the piston therein and. drive down the latter. Thereafter, and when the piston in the l) cylinder is near the end of its down 01' power stroke. the piston in the A cylinder is almost at the end at its lip-stroke. and therefore this cylinder is about ready to haus't; and this is the same situation which of operations just described; During subsequent running of the engine operations is repeated once for each complete ,1 revolution of the crank-shaft ld in the dion air, this cycle of rection of the arrows 10, until the engine is i put on fuel.

\Vhen it is desired to run the engine on fuel, the flow of compressed air from pipe is discontinued and the spring 38 returns the valve piston 37 to its normal or inactive position, when the intermediate chamber -26 of valve 23 is permanently placed in communication with the atmosphere by way of chambers 36 and 35 of valve At the beginning oi eluding notion or down-stroke oi the piston 6 in the A.

cylinder, valve piston 27 is on its way down from its illustrated position and has almost reached its lowermost position, and during such downstroke of the piston in the A cylinder air is drawn into the A cylinder from the atmosphere through port 35 and chambers 35, 36, 26 and 25, because during this down-stroke of the piston in the A cylinder the valve piston .27 is descending to its lowermostposition and thereafter ascending toward its illustrated intermediate position. .\Ieanwhile, the piston in the 1) cylinder is making its up-stroke, and so a rush of air for scavenging is discharged from the li cylinder into the scavenger re ceiver 21 through the chamber 24. and over the valve piston 21, During the suction or down-stroke of the piston (S in the B cylinder the valve piston 27 is raised from its intermediate position to its highest position and then ldwered again to its '..lnstrated intermediate position, and air is drawn into the 1) cylinder through port 35' and chambers 35, 3G, 26 and Q-l. While the valve piston 27 is thus rising above aml descemling back to its intermediate position, the piston (i in the A cylinder is making its up-strokc. and so a rush of air for scavenging is discharged from the A cylinder into the scavenger receiver 21 through the chamber 25 and up through the hollow valve piston 27. v Duringsubsequent running of the engine on this cycle of operations is repeated once for each complete revolution of the crank-shaft 10 in the direction of the arrows 0' until. the engine is stopped. either oneof the working pistons 5 reaches its lowermost position it uncovers the ports I!) and 20 and air from the scavenger receiver l1 rushes through the port 15) into the cylinder. 'lheim-oming'air is deflected upward into the cylinder by a deflecting surface, 5 on the end of the piston, thereby effecting a thorough scavenging of the cvlinder, the burned gases being forced out through the port 20 into the exhaust header 22. As the working piston rises. the air in the cylinder is compressed within the combustion chamber 3 into which the fuel is sprayed through the spray valve 4 which is opened, as above described, and the fuel is ignited by the heat due to the compression of the air in the combustion chamber.

The pipe 31- may receive its compressed air from any suitable source, as stated. However, a conventional type of air compressor 37 is shown as having its piston (38 dr ven by the engine shaft '10, a piston rod (it) being connected to the piston and to the engine shaft. During running of the engine. the air delivered from this compressor may be lead to a suitable storage tank (not shown) having an outlet leading to pipe It-l.

In order to reverse the engine, it is necessary to change the timing of the various valves and th1s is accomplished by shifting the cam shafts 11 and 82. These cam shafts are connected to shafts 43 and 44 (Fig. 6) respectively by similar sleeves 45 and 46 which are slidable longitudinally with respect to the shafts 43 and 44, being connected thereto by feathered keys 47 and 48. The shafts 43 and 44 are positively driven from the crank shaft 10 by suitable gearing, such for instance as the gears 49, 50 and 51, these gears being so proportioned that the shafts 43 and 44 rotate at the same speed as the crank shaft. The sleeves 45 and 46 are provided at their inner ends with teeth 52 and engaging spiral threads 54 and formed on the ends of the cam shafts 11 and 3;. The threads 55 ,on the cam shaft 32 are of greater pitch than the threads 54 on the cam shaft ll, so that the same extent of angular movement of shafts 32 and 11 is portions 56 and 57 forming shoulders 58 and 59 adapted to be engaged by the teeth 52 and 53. 'lheheadcd portion 59 is longerthan the headed portion 58 by an amount equal to the distance between the cams 41 and 42 which a re tixed to the cam shaft 32. Furthermore, the two headed portions are provided with axial recesses ()0 which receive the ends of the shafts 43 and 44 and the recess for shaft 44 is of much greater depth than that for the shaft 43. The sleeves 45 and 46 are arranged to be shifted in any suitable manne as by collars lying in grooves ()2 and engaged by forks on a rock shaft 3 adapted to be actuated by a hand lever 64'. Assuming At their outer ends the cam shafts ll and 32 are provided with Headed as shown in Fig. 6, if it be desired to change the direction of operation of the engine, the

hand lever )l is actuated to shift the sleeves to their outermost positions, both sleeves being moved through the same distance in passing from one cxtrcmc position to the other. When the sleeves have tiavcleda dis tance such that the teeth 53 on the sleeve 46 engage the shoulder 59, the cam shaft 32 will have been rotated the desired amount to elicit the correct change in the timing of thevalve 27, but the cam shaft 11 will not have been rotated the desired amount to effect the correct. timing of the spray valves, as the pitch of the threads 54 is greater than that of the threads 55, andthe teeth 52 of the sleeve so will not have engaged the shoulder 58 due to the factthat the headed portion 56 is shorter than the headed portion In the further outward movement of the sleeves, the turning movement of shaft 11/ is con pleted by the threads 54: and the teeth 52 on sleeve Also, the teeth on sleeve 46 engaging the headed end 59 of shaft 32 move that shaft along with the sleeve a distance equal to the axial distance between cams 41 and 42 such that one of those cams is substituted for the other as the actuator of valve 37. Such movement of shaft 32 is provided for by making the opening for shaft 44 in the headed end 57 of sutliciently great depth. Such movement of shaft 32 does not affect the cam or eccentric 31 since it is splined on the shaft and prevented from moving axially by the adjacent hearings in The cam shafts which the shaft is mounted. are shifted to occupy their original positions in a similar manner when the sleeves are moved from their outer to their inner positions with the exception that, in this instance, longitudinal movement of the shaft 32 is effected by the engagement of the shoulder 66 of the sleeve to with the outer end of the headed portion 57. It will thus be seen the reversal of the engine is effected by movement of the hand lever 64 and that the movement of reversal also places the starting mechanism in condition for starting the engine in the reverse direction. T he operation of the reversing lever results in turning both cam shafts angularly in their bearings a predetermined amount and one of the shafts is also moved axially so as to substitute one cam for another as the means fo? actuating the inlet valve for the compressed air for starting.

The-'construction herein illustrated and described is one which may be employed in util zing the invention. but it will be understood that the invention is not limited to any specific construction. Changes in design, construction and arraifgement of the parts, we consider to be within the scope of the invention and we aim to include them within the terms of the claims appended hereto.

What we claim is: 1. An internal combustion engine comprising the combination of two working cylinders, two scavenger cylinders, pistons in the cylinders, a receiver connected to the Working cylinders by ports controlled by the pistons those cylinders, a valve, means "tor causing theeng'ine to actuate said valve to successively connect the scavenger cylinders'alternately to the receiver and to atmosphere, a source"of supply of compressed air, a second valve and means for causing the engine to operate the second valve to disconnect the first valve from/the atmosphere and connect it to the source of supply of compressed air; substantially as described.

2. An internal combustion engine comprising the combination of two working cylinders, two scavenger cylinders, pistons in the cylinders, ports in the working cy1inders controlled by the pistons therein, a valve movable to successively connect the scavenger cylinders alternately to one of said ports and to atmosphere, so that when one cylinder is connected to one of said ports the other cylinder is connected to at mosphere and vice versa, a cam for actuating" said valve, means for rotating the cam from the engine shaft, and means for varying the relation of the cam to the engine shaft substantially as described.

An internal combustion engine com.

prising the combination of a working cylinder, a scavenging cylinder, pistons therein. a valve controlling; the connection of the scavenging cylinder to the working cylinder and to atmosphere, a source of supply of compressed ail, a second valve movable to disconnect the first valve from atmosphere and connect it to said source, means for actuating said valves, and means for normally holding the second valve out of coaction with said actuating means; substantially as described.

4. A reversible internal combustion engine comprising the combination of an engine-shaft, a cylinder, a piston'therein, a source of supply of compressed air to be admitted to the cylinder to start the engine, a cam shaft drivenby the engine shaft, a plurality of cams fixed on the cam-shaft, valve mechanism operated by the cam shaft and controlling the ope 'ation of the engine, said valve mechanism including a valve operated by one of said cams when the engine is running in one direction and by the' other of said cams when the engine is running in the other direction, and a single means for moving the cam shaft spirally relative to the engine shaft to effect reversal of the engine; substantially as describe 5. A reversible internal combustion ongine, comprising the combination. of aniongine shaft, a cylinder, a. piston. therein, airstarting valve mechanism for the cylinder,

a cam-shaft driven by the engine for operating saio valve fllBCllflfllSfll, a spray-valve, a second cam-shaft driven by the engine for opcrating; the spray-valve, and means for moving both cam-shafts spirally but different amounts to effect reversal of the onnine; substantially as described.

6. An internal combustion engine comprising the combination of two working cylinders, two scavenger cylinders, pistons in the cylinders, ports in the working cylinders controlled by .the pistons therein, a valve movable to successively connect the scavenger cylinders alternately to one of .of supply each time the first valve is connected to one of the scavenger cylinders; substantially as described.

7. An internal combustion engine comprising the combination of a working cylinder, a scavenging cylinder, pistons therein, a. valve controlllng the connection of the scavenging cylinder to the working cylinder and to atmosphere, a source of supply of compressed air, a second valve movable to disconnect the first valve from atmosphere and connect it to said source, means for actuating said valves, and means for normally holding the second valve 'out of coaction with said actuating means, the admission of air from said source of supply to the second valve overcoming said last-named means whereby the said actuating means may actuate the second valve; substantially as described.

8. An internal combustion engine, comprising the combination of two working cylinders, two scavenging cylinders, an airstarting valve, a second valve, a plurality of connections between the second valve and the various cylinders, a connection between the two valves, different positions of the second valve putting various ones of said plurality of connections in communication with the connection last mentioned, a connection between the air-starting valve and a source of compressed air supply, a connecof connections between the second valve.

and the various cylinders, a connection be-, tween the two valves, different positions of the second valve putting various ones of said plurality of connections in communication with the connection last mentioned, a connection between the air-starting valve and a source of compressed air supply, a connection between the air-starting valve and the atmosphere, different positions of the air-starting valve putting different ones of the two connections last mentioned in communication with the connection between the two valves, means for holding the airstarting valve in the position wherein the connection between the two valves is continuously open to the atmosphere, and means for operating the second valve periodically to permit running of the engine on air; substantially as described.

In testimony whereof we afiix our signatures, in presence of two witnesses.

GREGORY G. DAVISON. JOHN W. ANDERSON. Witnesses: F. L. BLAKE,

ANNA K. FLETCHER. 

